/*
 * KVStoreTest.actor.cpp
 *
 * This source file is part of the FoundationDB open source project
 *
 * Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <ctime>
#include "fdbserver/workloads/workloads.h"
#include "fdbserver/IKeyValueStore.h"
#include "flow/ActorCollection.h"
#include "flow/actorcompiler.h"  // This must be the last #include.

extern IKeyValueStore *makeDummyKeyValueStore();

template <class T>
class Histogram {
public:
	Histogram(int minSamples = 100) : minSamples(minSamples) { reset(); }

	void reset(){
		N = 0;
		samplingRate = 1.0;
		sum = T();
		sumSQ = T();
	};

	void addSample(const T& x){
		if (!N){
			minSample = maxSample = x;
		} else {
			if (x < minSample) minSample = x;
			if (maxSample < x) maxSample = x;
		}
		sum += x;
		sumSQ += x*x;
		N++;
		if (g_random->random01() < samplingRate){
			samples.push_back(x);
			if (samples.size() == minSamples * 2){
				g_random->randomShuffle(samples);
				samples.resize(minSamples);
				samplingRate /= 2;
			}
		}
	}
//	void addHistogram(const Histrogram& h2);

	T mean() const { return sum * (1.0 / N);	} // exact
	const T& min() const { return minSample; }
	const T& max() const { return maxSample; }
	T stdDev() const {
		if (!N) return T();
		return sqrt((sumSQ * N - sum*sum) * (1.0 / (N*(N-1))));
	}
	T percentileEstimate(double p){
		ASSERT(p <= 1 && p >= 0);
		int size = samples.size();
		if (!size) return T();
		if (size == 1) return samples[0];
		std::sort(samples.begin(), samples.end());
		double fi = p * double(size-1);
		int li = p * double(size-1);
		if (li == size-1) return samples.back();
		double alpha = fi-li;
		return samples[li]*(1-alpha) + samples[li+1]*alpha;
	}
	T medianEstimate() { return percentileEstimate(0.5); }
	uint64_t samplesCount() const { return N; }

private:
	int minSamples;
	double samplingRate;
	std::vector<T> samples;
	T minSample;
	T maxSample;
	T sum;
	T sumSQ;
	uint64_t N;
};

struct KVTest {
	IKeyValueStore* store;
	Version startVersion;
	Version lastSet;
	Version lastCommit;
	Version lastDurable;
	Map<Key, IndexedSet<Version, NoMetric>> allSets;
	int nodeCount, keyBytes;
	bool dispose;

	explicit KVTest(int nodeCount, bool dispose, int keyBytes)
		: store(NULL),
		  dispose(dispose),
		  startVersion( Version(time(NULL)) << 30 ),
		  lastSet(startVersion), lastCommit(startVersion), lastDurable(startVersion),
		  nodeCount(nodeCount),
		  keyBytes(keyBytes)
	{
	}
	~KVTest() {
		close();
	}
	void close() {
		if (store) {
			TraceEvent("KVTestDestroy");
			if (dispose)
				store->dispose();
			else
				store->close();
			store = 0;
		}
	}

	Version get(KeyRef key, Version version) {
		auto s = allSets.find(key);
		if (s == allSets.end()) return startVersion;
		auto& sets = s->value;
		auto it = sets.lastLessOrEqual(version);
		return it!=sets.end() ? *it : startVersion;
	}
	void set( KeyValueRef kv ) {
		store->set(kv);
		auto s = allSets.find(kv.key);
		if (s == allSets.end()) {
			allSets.insert( MapPair<Key,IndexedSet<Version, NoMetric>>(Key(kv.key), IndexedSet<Version, NoMetric>()) );
			s = allSets.find(kv.key);
		}
		s->value.insert( lastSet, NoMetric() );
	}

	Key randomKey() { return makeKey( g_random->randomInt(0,nodeCount) ); }
	Key makeKey(Version value) {
		Key k;
		((KeyRef&)k) = KeyRef( new (k.arena()) uint8_t[ keyBytes ], keyBytes );
		memcpy( (uint8_t*)k.begin(), doubleToTestKey( value ).begin(), 16 );
		memset( (uint8_t*)k.begin()+16, '.', keyBytes-16 );
		return k;
	}
};

ACTOR Future<Void> testKVRead( KVTest* test, Key key, Histogram<float>* latency, PerfIntCounter* count ) {
	//state Version s1 = test->lastCommit;
	state Version s2 = test->lastDurable;

	state double begin = timer();
	Optional<Value> val = wait( test->store->readValue(key) );
	latency->addSample( timer() - begin );
	++*count;
	Version v = val.present() ? BinaryReader::fromStringRef<Version>( val.get(), Unversioned() ) : test->startVersion;
	if (v < test->startVersion) v = test->startVersion;  // ignore older data from the database

	//ASSERT( s1 <= v || test->get(key, s1)==v );  // Plan A
	ASSERT( s2 <= v || test->get(key, s2)==v );  // Causal consistency
	ASSERT( v <= test->lastCommit );  // read committed
	//ASSERT( v <= test->lastSet );  // read uncommitted
	return Void();
}

ACTOR Future<Void> testKVReadSaturation( KVTest* test, Histogram<float>* latency, PerfIntCounter* count ) {
	while (true) {
		state double begin = timer();
		Optional<Value> val = wait( test->store->readValue(test->randomKey()) );
		latency->addSample( timer() - begin );
		++*count;
		wait(delay(0));
	}
}

ACTOR Future<Void> testKVCommit( KVTest* test, Histogram<float>* latency, PerfIntCounter* count ) {
	state Version v = test->lastSet;
	test->lastCommit = v;
	state double begin = timer();
	wait( test->store->commit() );
	++*count;
	latency->addSample( timer() - begin );
	test->lastDurable = std::max( test->lastDurable, v );
	return Void();
}

Future<Void> testKVStore( struct KVStoreTestWorkload *const& );

struct KVStoreTestWorkload : TestWorkload {
	bool enabled, saturation;
	double testDuration, operationsPerSecond;
	double commitFraction, setFraction;
	int nodeCount, keyBytes, valueBytes;
	bool doSetup, doClear, doCount;
	std::string filename;
	PerfIntCounter reads, sets, commits;
	Histogram<float> readLatency, commitLatency;
	double setupTook;
	std::string storeType;

	KVStoreTestWorkload( WorkloadContext const& wcx )
		: TestWorkload(wcx), reads("Reads"), sets("Sets"), commits("Commits"), setupTook(0)
	{
		enabled = !clientId; // only do this on the "first" client
		testDuration = getOption( options, LiteralStringRef("testDuration"), 10.0 );
		operationsPerSecond = getOption( options, LiteralStringRef("operationsPerSecond"), 100e3 );
		commitFraction = getOption( options, LiteralStringRef("commitFraction"), .001 );
		setFraction = getOption( options, LiteralStringRef("setFraction"), .1 );
		nodeCount = getOption( options, LiteralStringRef("nodeCount"), 100000 );
		keyBytes = getOption( options, LiteralStringRef("keyBytes"), 8 );
		valueBytes = getOption( options, LiteralStringRef("valueBytes"), 8 );
		doSetup = getOption( options, LiteralStringRef("setup"), false );
		doClear = getOption( options, LiteralStringRef("clear"), false );
		doCount = getOption( options, LiteralStringRef("count"), false );
		filename = getOption( options, LiteralStringRef("filename"), Value() ).toString();
		saturation = getOption( options, LiteralStringRef("saturation"), false );
		storeType = getOption( options, LiteralStringRef("storeType"), LiteralStringRef("ssd") ).toString();
	}
	virtual std::string description() { return "KVStoreTest"; }
	virtual Future<Void> setup( Database const& cx ) { return Void(); }
	virtual Future<Void> start( Database const& cx ) {
		if (enabled)
			return testKVStore(this);
		return Void();
	}
	virtual Future<bool> check( Database const& cx ) { return true; }
	void metricsFromHistogram(vector<PerfMetric>& m, std::string name, Histogram<float>& h){
		m.push_back( PerfMetric( "Min " + name, 1000.0 * h.min(), true) );
		m.push_back( PerfMetric( "Average " + name, 1000.0 * h.mean(), true) );
		m.push_back( PerfMetric( "Median " + name, 1000.0 * h.medianEstimate(), true) );
		m.push_back( PerfMetric( "95%% " + name, 1000.0 * h.percentileEstimate(0.95), true) );
		m.push_back( PerfMetric( "Max " + name, 1000.0 * h.max(), true) );
	}
	virtual void getMetrics( vector<PerfMetric>& m ) {
		if (setupTook) m.push_back( PerfMetric("SetupTook", setupTook, false) );

		m.push_back(reads.getMetric());
		m.push_back(sets.getMetric());
		m.push_back(commits.getMetric());
		metricsFromHistogram(m, "Read Latency (ms)", readLatency);
		metricsFromHistogram(m, "Commit Latency (ms)", commitLatency);
	}
};

WorkloadFactory<KVStoreTestWorkload> KVStoreTestWorkloadFactory("KVStoreTest");

ACTOR Future<Void> testKVStoreMain( KVStoreTestWorkload* workload, KVTest* ptest ) {
	state KVTest& test = *ptest;
	state ActorCollectionNoErrors ac;
	state std::deque<Future<Void>> reads;
	state BinaryWriter wr(Unversioned());
	state int64_t commitsStarted = 0;
	//test.store = makeDummyKeyValueStore();
	state int extraBytes = workload->valueBytes - sizeof(test.lastSet);
	ASSERT( extraBytes >= 0 );
	state char* extraValue = new char[extraBytes];
	memset(extraValue, '.', extraBytes);

	if (workload->doCount) {
		state int64_t count = 0;
		state Key k;
		state double cst = timer();
		while (true) {
			Standalone<VectorRef<KeyValueRef>> kv = wait( test.store->readRange( KeyRangeRef(k, LiteralStringRef("\xff\xff\xff\xff")), 1000 ) );
			count += kv.size();
			if (kv.size() < 1000) break;
			k = keyAfter( kv[ kv.size()-1 ].key );
		}
		double elapsed = timer()-cst;
		TraceEvent("KVStoreCount").detail("Count", count).detail("Took", elapsed);
		printf("Counted: %lld in %0.1fs\n", count, elapsed);
	}

	if (workload->doSetup) {
		wr << Version(0);
		wr.serializeBytes(extraValue, extraBytes);

		printf("Building %d nodes: ", workload->nodeCount);
		state double setupBegin = timer();
		state double setupNow = now();
		state Future<Void> lastCommit = Void();
		state int i;
		for(i=0; i<workload->nodeCount; i++) {
			test.store->set( KeyValueRef( test.makeKey( i ), wr.toStringRef() ) );
			if (!((i+1) % 10000) || i+1==workload->nodeCount) {
				wait( lastCommit );
				lastCommit = test.store->commit();
				printf("ETA: %f seconds\n", (timer()-setupBegin) / i * (workload->nodeCount-i));
			}
		}
		wait( lastCommit );
		workload->setupTook = timer()-setupBegin;
		TraceEvent("KVStoreSetup").detail("Count", workload->nodeCount).detail("Took", workload->setupTook);
	}

	state double t = now();
	state double stopAt = t + workload->testDuration;
	if (workload->saturation) {
		if (workload->commitFraction) {
			while (now() < stopAt) {
				for(int s=0; s<1/workload->commitFraction; s++)
				{
					++test.lastSet;
					BinaryWriter wr(Unversioned()); wr << test.lastSet;
					wr.serializeBytes(extraValue, extraBytes);
					test.set( KeyValueRef( test.randomKey(), wr.toStringRef() ) );
					++workload->sets;
				}
				++commitsStarted;
				wait( testKVCommit( &test, &workload->commitLatency, &workload->commits ) );
			}
		} else {
			vector<Future<Void>> actors;
			for(int a=0; a<100; a++)
				actors.push_back( testKVReadSaturation( &test, &workload->readLatency, &workload->reads ) );
			wait( timeout( waitForAll(actors), workload->testDuration, Void() ) );
		}
	} else {
		while (t < stopAt) {
			double end = now();
			loop {
				t += 1.0 / workload->operationsPerSecond;
				double op = g_random->random01();
				if (op < workload->commitFraction) {
					// Commit
					if (workload->commits.getValue() == commitsStarted) {
						++commitsStarted;
						ac.add( testKVCommit( &test, &workload->commitLatency, &workload->commits ) );
					}
				} else if (op < workload->commitFraction+workload->setFraction) {
					// Set
					++test.lastSet;
					BinaryWriter wr(Unversioned()); wr << test.lastSet;
					wr.serializeBytes(extraValue, extraBytes);
					test.set( KeyValueRef( test.randomKey(), wr.toStringRef() ) );
					++workload->sets;
				} else {
					// Read
					ac.add( testKVRead( &test, test.randomKey(), &workload->readLatency, &workload->reads ) );
				}
				if (t >= end) break;
			}
			wait( delayUntil(t) );
		}
	}

	if (workload->doClear) {
		state int chunk = 1000000;
		t = timer();
		for(i = 0; i < workload->nodeCount; i+=chunk) {
			test.store->clear( KeyRangeRef(  test.makeKey( i ),  test.makeKey( i + chunk ) ) );
			wait( test.store->commit() );
		}
		TraceEvent("KVStoreClear").detail("Took", timer() - t);
	}

	return Void();
}

ACTOR Future<Void> testKVStore(KVStoreTestWorkload* workload) {
	state KVTest test( workload->nodeCount, !workload->filename.size(), workload->keyBytes );
	state Error err;

	//wait( delay(1) );
	TraceEvent("GO");

	UID id = g_random->randomUniqueID();
	std::string fn = workload->filename.size() ? workload->filename : id.toString();
	if (workload->storeType == "ssd")
		test.store = keyValueStoreSQLite( fn, id, KeyValueStoreType::SSD_BTREE_V2);
	else if (workload->storeType == "ssd-1")
		test.store = keyValueStoreSQLite( fn, id, KeyValueStoreType::SSD_BTREE_V1);
	else if (workload->storeType == "ssd-2")
		test.store = keyValueStoreSQLite( fn, id, KeyValueStoreType::SSD_REDWOOD_V1);
	else if (workload->storeType == "ssd-redwood-experimental")
		test.store = keyValueStoreRedwoodV1( fn, id );
	else if (workload->storeType == "memory")
		test.store = keyValueStoreMemory( fn, id, 500e6 );
	else
		ASSERT(false);

	wait(test.store->init());

	state Future<Void> main = testKVStoreMain( workload, &test );
	try {
		choose {
			when ( wait( main ) ) { }
			when ( wait( test.store->getError() ) ) { ASSERT( false ); }
		}
	} catch (Error& e) {
		err = e;
	}
	main.cancel();

	Future<Void> c = test.store->onClosed();
	test.close();
	wait( c );
	if (err.code() != invalid_error_code) throw err;
	return Void();
}
